316 research outputs found

    Qualification plan for the ultraviolet spectrometer experiment (S-169), revision A

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    The qualification methods used to verify that the UVS hardware meets the technical requirements of the contract are defined. Included in this plan are test location, the qualification UVS to be tested, test objectives, and all tests required to verify that the UVS meets all performance and environmental requirements of the CEI specification. Additionally, environmental test conditions, testing time or cycles, allowable maintenance, logging requirements, manner of analysis, and utilization of test results, disposition of test specimens, failure criteria, retest requirements, facilities and support requirements, and the time phasing of the tests are presented

    Proposal for a direct numerical control system

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    This report describes a Direct Numerical Control (DNC) System proposed for use in the LLL Mechanical Shops. The DNC system includes a small digital computer that will provide the capability to store, manipulate, and distribute parts programs to the various machine tool stations. The system will also provide editing capabilities for parts program development and optimization. Diagnostic routines will be included to provide preventive maintenance. Logging of machine on'' time can be instituted to provide data for improved scheduling and machine tool usage. (auth

    The Use of Long-Term Modelling in Analysing N\u3csub\u3e2\u3c/sub\u3eO Abatement Strategies in Dairy Pastures

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    Concerns about the environmental impact of nitrogen (N) losses in Australia, in particular, nitrous oxide emissions are related to the rapid increase in N application on dairy pastures. Computer modelling is the most suitable method available to assess the potential of best management practices (BMP) to reduce field losses, as direct field measurements are frequently limited by the short term nature of many field trials

    Comparison of Summer Forages and the Effect of Nitrogen Fertilizers on \u3ci\u3eBrassica\u3c/i\u3e Forages in Tasmania

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    Summer forage crops, and in particular Brassica spp., have become increasingly popular in dairy production systems in Tasmania. Field experiments were conducted for 3 years in northwestern Tasmania, in the spring/summers beginning in 1995. The study aimed to compare yield and quality of Brassica and Poaceae forages and the response of Brassica species to nitrogen (N) (50, 100 and 200 kg N/ha) and irrigation. The average total yields of dryland (rainfed) crops in 1995 to 1997 experiments, were turnip (Brassica rapa) 9.3 t/ha, rape (B. napus) 5.9 t/ha, oats (Aevena sativa) 5.2 t/ha, kale (B. oleracea) 5.1 t/ha, short-lived ryegrass (Lolium multiflorum) 5.1 t/ha, pasja (B. campestris × B. napus) 4.3 t/ha, perennial ryegrass (L. perenne) 4.2 t/ha, millet (Echinochloa utilis) 3.8 t/ha, and maize. (Zea mays) 2.9 t/ha. Irrigation increased the yield of turnips by 4.8 t/ha (mainly bulbs) and millet yields by 1.4 t/ha and reduced maize yield by 1.2 t/ha. Brassica species were higher in ME and lower in CP than the Poaceae forages. Nitrogen fertilizer increased the DM yield of tops of all Brassica crops in the 1997/98 experiments under irrigation, but it decreased the yield of turnips bulbs. The total yields with 50, 100 and 200 kg N/ha were 14, 15.2 and 15 t DM/ha for turnips, 7.5, 8.5 and 10 t for pasja and 10, 12 and 12.2 t DM/ha for rape, respectively. With 100 kg N/ha the average concentration of quality attributes of turnips, pasja and rape were CP 14, 22 and 19%, ME 12, 14.6 and 12.6 MJ/kg DM respectively. Nitrogen increased the CP, but had no effect on ME of any Brassica crops. Brassica forage are superior to Poaceae forages for summer feed production and as a part of pasture renovation process. They are higher in their yields, quality and water use efficiency and respond well to N fertilizer

    An evaluation of carbon offset supplementation options for beef production systems on coastal speargrass in central Queensland, Australia

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    In 2014, the Australian Government implemented the Emissions Reduction Fund to offer incentives for businesses to reduce greenhouse gas (GHG) emissions by following approved methods. Beef cattle businesses in northern Australia can participate by applying the 'reducing GHG emissions by feeding nitrates to beef cattle' methodology and the 'beef cattle herd management' methods. The nitrate (NO3) method requires that each baseline area must demonstrate a history of urea use. Projects earn Australian carbon credit units (ACCU) for reducing enteric methane emissions by substituting NO3 for urea at the same amount of fed nitrogen. NO3 must be fed in the form of a lick block because most operations do not have labour or equipment to manage daily supplementation. NO3 concentrations, after a 2-week adaptation period, must not exceed 50 g NO3/adult animal equivalent per day or 7 g NO3/kg dry matter intake per day to reduce the risk of NO3 toxicity. There is also a 'beef cattle herd management' method, approved in 2015, that covers activities that improve the herd emission intensity (emissions per unit of product sold) through change in the diet or management. The present study was conducted to compare the required ACCU or supplement prices for a 2% return on capital when feeding a low or high supplement concentration to breeding stock of either (1) urea, (2) three different forms of NO3 or (3) cottonseed meal (CSM), at N concentrations equivalent to 25 or 50 g urea/animal equivalent, to fasten steer entry to a feedlot (backgrounding), in a typical breeder herd on the coastal speargrass land types in central Queensland. Monte Carlo simulations were run using the software @risk, with probability functions used for (1) urea, NO3 and CSM prices, (2) GHG mitigation, (3) livestock prices and (4) carbon price. Increasing the weight of steers at a set turnoff month by feeding CSM was found to be the most cost-effective option, with or without including the offset income. The required ACCU prices for a 2% return on capital were an order of magnitude higher than were indicative carbon prices in 2015 for the three forms of NO3. The likely costs of participating in ERF projects would reduce the return on capital for all mitigation options. © CSIRO 2016

    Nitrogen Balances in High Rainfall, Temperate Dairy Pastures of South Eastern Australia

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    Nitrogen (N) fertilizer use on dairy pastures in south eastern Australia has increased exponentially over the past 15 years, causing increasing environmental concerns. Volatilisation, denitrification and leaching of N were measured for one year (1998-1999) in pastures receiving no N fertilizer (grass/clover), or 200 kg N/ha applied as urea (46%N) or ammonium nitrate (34.5%N). Nitrogen balances were calculated for each treatment. Significantly more N was lost through volatilisation and denitrification when N was applied as urea compared to ammonium nitrate. Nitrate leaching losses were significantly greater with the application of N fertilizer, although the maximum loss was only 4.1 kg N/ha due to low rainfall between May and September. Nitrogen balances were -15, +87 and +82 kg N/ha per year for the grass/clover, 200 kg N/ha urea and 200 kg N/ha ammonium nitrate treatments, respectively. Given the large range in N losses and balances, there is opportunity for improving the N efficiency in dairy pastures, through lower stocking rates and more tactical use of grain and N fertilizer

    Weight gain and enteric methane production of cattle fed on tropical grasses

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    Context: Planted grasses are becoming an increasingly important feed resource for tropical smallholder ruminant production; yet, limited research has been conducted to quantify productivity or enteric methane (CH4_4) production of animals consuming these grasses. Aim: An experiment was conducted to assess yields and nutritional attributes of the following three tropical grasses: Cenchrus purpureus var. Kakamega 1 (Napier), Chloris gayana var. Boma (Rhodes) and Urochloa brizantha var. Xaeres (Brachiaria), and quantify enteric CH4_4 production of cattle fed on them. Methods: Yearling Boran steers (n:18; initial liveweight 216 ± 5.8 kg (mean ± s.e.m.) were allocated to one of three grasses, in a completely randomised design and fed ad libitum for two feeding periods, each period lasting for 70 days. Intake, liveweight (LW), apparent total-tract digestibility and enteric CH4_4 production were assessed. The grasses used were grown on site and biomass yields were monitored over a 2-year period. Animal growth was also simulated to a final weight of 350 kg, and the amount of feed and size of land required to produce, and days to reach final weight, were estimated. Key results: Mean voluntary dry-matter intake (DMI) and ADG were higher (P 0.05) within period. Methane yield (MY; CH4_4 g/DMI kg) was similar among treatments (26.7–28.5, P = 0.26) but Napier had a higher CH4_4 conversion factor [Ym; CH4_4 (MJ)/gross energy intake (MJ)] than did Rhodes and Brachiaria (0.0987 vs 0.0873 and 0.0903 respectively; P = 0.013). Our modelling indicated that steers consuming Rhodes took at least 30 more days to reach the target LW, required larger land area for feed production and produced more enteric CH4_4 than did the other two diets. Conclusion: Even though animal performance and MY among treatments did not differ, the animals had higher MY and Ym_m than currently estimated by the Intergovernmental Panel on Climate Change. Implication: The three grasses supported similar animal growth rate, implying that growing of higher-yielding grasses such as Napier offers an opportunity to optimise land productivity in the tropics. However, suitable feeding practices such as protein supplementation need to be explored to enhance ruminant production and reduce enteric CH4_4 production

    Integrating climate change mitigation and adaptation in agriculture and forestry: opportunities and trade-offs

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    This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.International audienceAlthough many activities can jointly contribute to the climate change strategies of adaptation and mitigation, climate policies have generally treated these strategies separately. In recent years, there has been a growing interest shown by practitioners in agriculture, forestry, and landscape management in the links between the two strategies. This review explores the opportunities and trade-offs when managing landscapes for both climate change mitigation and adaptation; different conceptua-lizations of the links between adaptation and mitigation are highlighted. Under a first conceptualization of 'joint outcomes,' several reviewed studies analyze how activities without climatic objectives deliver joint adaptation and mitigation outcomes. In a second conceptualization of 'unintended side effects,' the focus is on how activities aimed at only one climate objective—either adaptation or mitigation—can deliver outcomes for the other objective. A third conceptualization of 'joint objectives' highlights that associating both adaptation and mitigation objectives in a climate-related activity can influence its outcomes because of multiple possible interactions. The review reveals a diversity of reasons for mainstreaming adaptation and mitigation separately or jointly in landscape management. The three broad conceptualizations of the links between adaptation and mitigation suggest different implications for climate policy mainstreaming and integration
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